Collapsing tap



J. FRASER.

COLLAPSING TAP.

APPLICATION FILED JAN 17, 1916.

1,393,995. Patented Oct. 18, 1921.

2 S HEETSSHEET I.

J. FRASER.

COLLAPSING TAP.

AFPLICATION FILED JAN.17, I916. 1,393,995. Patented 001;. 18, 1921.

2 SHEETS-SHEET 2.

UNITED STATES PATENT OFFICE.

JAMES FRASER, 0F WILMINGTON, DELAWARE, ASSIGNOR TO THE GEOMETRIC TOOL 00., OF NEW HAVEN, CONNECTICUT, A CORPORATION.

COLLAPSIN G TAP.

Application filed Januaiy 17, 1916.

To all whom it may concem:

Be it known that I, JAMES FRASER, a citizen of the United States, residing at Wilmington, in the county of New Castle and State of Delaware, have invented a new and useful Improvement in Collapsing Taps; and I do hereby declare the following, when taken in connection with the accompanying drawings and the characters of reference marked thereon, to be a full, clear, and exact description of the same, and which said drawings constitute part ofthis application, and represent, in-

Figure 1 a view partly in front eleva tion and partly in vertical section of a collapsing tap constructed in accordance with my, invention.

Fig.2 a view thereof in side elevation on the half scale.

Fig. 3 a view of my improved tap in vertical longitudinal section, on the line a?) of Fig. 1. p

Fig. 4 a view of the tap in front elevation with its pair of threading dies or chasers in their collapsed positions.

Fig. 5a broken view of the tap in horizontal section.

Fig. 6 a detached perspective view of one of the two threading-dies or chasers.

My invention relates to an improved collapsing tap, the object being to produce a superior tool constructed with particular reference to the tapping of smaller diameters than is possible with the collapsing taps now in common use.

lVith these ends in view, my invention consists in a collapsing tap :having two chasers arranged to move in right lines with respect to each other so as to overlap in collapsing.

- My invention further consists in certam details of construction and combinations of parts as will-be hereinafter described and pointed out in the claims.

As herein shown, I employ an upper threading-die or chaser 2 and a similar lower threading-die or chaser 3, each having a substantially semicular stem 4; provided with a flat bearing-face 5, transversely arranged cutting-teeth 6 and a longitudinal clearancegroove 7. Each of the said threading-dles or chasers also has a base-plate 8 formed Specification of Letters Patent.

Patented Oct. 18,1921.

Serial No. 72,579. I

with two screw-holes 9 andupon its outer face with a positioning-rib 10 which latter is arranged at a right angle to the stem a whlch projects from the outer edge of the plate 8 at a right angle to the said edge.

The base-plates 8 of the said chasers 2 and 3 are respectively mounted in an upper chaser-carrier or slide 11 and a lower chaser-carrier or slide 12, so that the fiat bearing-faces 5 of the stems 4: slide upon each other transversely when the chasers are moved in opposite directions into position to perform their work of tapping or cutting and reversely moved in being collapsed so as to be disengaged from the object out after their work is done. The said carriers 11 and 12, the inner faces of which also ride upon each other, are formed in the said faces with recesses 13 located opposite each other for the reception of the base-plates 8 of the respective threading-dies or chasers. Grooves 14: leading out of the bottom of the recesses 13 are provided for the reception of the ribs 10 of the base-plates. Screws 15 passing through the screw-holes 9, as shown in Fig. 5, are employed for securing the plates 8 in the said grooves 13 of the respective slides 11 and 12.

As shown, the slides 11 and 12 are located in a deep slot 16 extending diametrically across the outer face of the head 17 of the tap,.and retained therein by means of two segmental retaining-plates 18 and 19 secured to the face of the head by means of screws 20. The said slides are formed upon their inner edges and near their respective ends,

each with a cam-slot 21 and a clearance-slot 22. The cam-slot 21 of the upper slide 1.1 receives a segmental cam 23 formed upon the forward face of an oscillating cam-ring 24 encircling the shoulder 25 of the head 17, while the cam-s1ot 21 of the slide 12 receives a segmental cam 26 formed upon the forward face of the ring 24 at a point diametrically opposite the segmental cam 23. An annular recess27 in the rear face of the ring 24: receives a helical spring 28 employed to turn the said ring on the shoulder 25 to cause the cams 23 and 26 to move the slides 11 and 12 in the direction required for collapsing the chasers. The ring 24 is released to the action of the spring 28,

by the retraction from the annular groove 27, of the head 29 of the tripping-pin 30 driven into a ring 31 mounted upon a bushing 32 laterally movable upon a shoulder 33 interposed between the head 17 and its shank 34, the said bushing 33 being laterally moved against slight frictional restraint by means of a yoke-shaped tripping-lever 35 suspended from a stud 36 in one end of a bracket 37 secured to the periphery of the head 17, the yoke 35 being connected with the bushing 32 for the operation thereof, by means of screw-trunnions 38. The means employed for engaging with the tripping-lever 35 may be of any approved form and mounted in any ordinary way upon the machine provided with the tap.

For resetting the tap after it'has been collapsed by the spring 28, I employ a handle 39 mounted in the cam-ring-24 which is held in its reset position against the tension of the spring 28, by means of the head 29 of the pin 30 when the head 29 has rentered the annular groove 27 in the usual manner.

To limit the rotation of the cam-ring 24 with respect to the head 17, I employ a stopplunger 40 the inner end of which enters a peripheral slot 41 in the shoulder 25 of the head 17, the said plunger being located'in a threaded sleeve 42 mounted in the ring 24. The plunger 40 is formed with a stem 43 having a knurled button 44 secured to its outer end by a pin 45. A helical spring 46 encircling the stem 43 and interposed between the outer end of the plunger and the outer end. of the sleeve 42, normally maintains the inner end of the plunger entered into the slot 41 the length of which determines the throw of the slides 11 and 12 and hence the relative movement in opposite directions of the threading-dies or chasers 2.

and 3. The cam-ring 24 is held against rearward displacement on the shoulder 25 by means of a disk 47 having a central opening to permit it to be passed over the shoulrler 33 of the hank 34 and held inplace by means of screws 48 entering the'rear face of the said shoulder 25 The said disk 17 is formed, as shown in Fig. 3, with a slot 49 i for the clearance of the-head 29 ofthe trip- 7 parallel planes instead of radially as heretoi space and so permit the-tapping of smaller foi'e,'ancl'tl1us' secure a great economy of diameters than has heretofore been possible with collapsing taps, since my improved chasers may, when required, be collapsed to the point to which their edges will register,

in which position they will only occupy a space equal to the width of the face 5 of either one of the chasers.

I do not, therefore, limit myself to any means for operating my improved threading-dies or chasers, my invention consisting broadly in constructing and arranging them so as to move in parallel planes so as to over- 7 lap whether in actual contact or otherwise. It will be noted that the cutting edges or teeth 6 of the chasers 2 and'3' are located 7 upon the sides of said chasers opposite their abutting faces, whereby the cutting strains on said chasers tend to force their abutting faces more tightly together. In'order to prevent the deflection of the longitudinal axes of the chasers outof parallelism, such construction, the sup- 1 the cutting-edges arelocated is provided by the two segmental retaining-plates 1 8 and 19 and the support upon the opposite sides, that is, upon those sides which comprise the abutting faces of the-chasers,sis provided by-the wall 16 0f the slot'16 in the head 17 of the tap. Thisconstruction provides an interlocking of-the chasers with the head 17 through the slides 11 and 12, as

will be apparent-when it is considered that by reason ofthe location of the cutting edges in the outer sides of the chasers the chasers areforced together by the cutting action and that by reason of the engagement of the retaining plates 18 and19 with the outer sides of'the chaser carrying slides 11 and 12 the forcing together of the chasers by the cutting action tends to drivextheir up? per ends tightly against the wall 16 of the slot 16. The result is that'the chasers and their carrying slides are so confined in the head 17 during the cutting operation as to constitute substantially jone' piece, the chasers being supported uponopposite sides.

of their cutting-edges against those strains which tend to cause their abutting faces to slide over each other and thus throw the lon- .gitudinal axes of the chasers outof parallelism. As above suggested, this support upon the outer side of the chasers is provided by the retaining plates '18 and19 and thesupport upon the inner side of the'chasers is provided both by the abutting of the chasers against'each other as'they are forced more tightly together in the cutting operation and their combined abutting against'the wall 16 of the slot 16'aga'inst which they are forced both directly by the reaction from the cutting strains and indirectly as a result of the reaction from the cutting strains against the retaining plates 18 and 19.

This support of the chasers upon opposite sides of the cutting edges against the cutting strains tending to deflect their longitudinal axes from parallelism is an important feature of the invention and although the illustrated construction is one particularly adapted for chasers having the cutting-edges located in the sides remotes from the abutting faces in such manner that the cutting action tends to force the abutting faces together, it will be understood that the invention is not restricted to the illustrated embodiment and that such support may be obtained in other ways in constructions in which other arrangements of the cuttingedges are provided.

1 claim 1. In a collapsing tap, the combination with a head having a slot extending diametrically across its outer face, of two slides located within the said slot in which they ride upon each other, and each of which has a cam-slot at one end and a clearance slot at its opposite end, two chasers respectively carried by the said slides in which they are located opposite each other, and an oscillating cam-ring encircling the said head and having two oppositely located segmental cams respectively passing through the cam-slot of one slide and the clearanceslot of the other slide, whereby by the oscillation of the said ring, the slides, and hence the chasers, are moved in right lines in opposite directions.

2. In a collapsing tap, the combination with ahead having a slot extending diametrically across its outer face, of two slides located within the said slot in which they ride upon each other, each of the said slides having a cam-slot located at one end and a clearance slot located at its opposite end, and oscillating cam-ring encircling the said head and having oppositely located segmental cams respectively passing through the cam slot of one slide and the clearance-slot of the other slide, and the said ring being formed upon its inner face with an annular recess, and a spring located within the said recess for turning the said ring with respect to the said head for moving the slides in opposite directions for collapsing the tap.

3. A tap or reamer comprising oppositely movable contacting slides each carrying a cutter comprising a base and an axially ex tending portion having a cutting edge on one side, one cutter partly overlapping the other in a plane through the axis of the tool, and a, relatively rotatable cam ring engaging and controlling said slides.

l. ln a tap or reamer, the combination with a pair of axially projecting cutters overlapping in a plane through the axis of the tool, of a ring having internal cam surfaces for moving said cutters in opposite directions.

5. A collapsing tap having a head, a pair of oppositely movable overlapping chasers carried thereby, and means for preventing the said chasers from being deflected from the parallelism of their longitudinal axes.

6. A collapsing tap having a head, a pair of oppositely movable overlapping chasers carried thereby, means for preventing the said chasers from being deflected from the parallelism of their longitudinal axes, and a rotary cam-ring applied to the said h ad and co-acting with the said chasers for controlling their movement in opposite dire-ntions.

7. A collapsing tap having a head, two oppositely movable contact slides mounted therein, two parallel overlapping chasers respectively carried by the said slides, means for interlocking the said slides with the said head for preventing the deflection of the longitudinal axes of the chasers from paraL lelism, and means for moving the said slides in opposite directions.

8. A collapsing tap having a head, two oppositely movable contact slides mounted therein, two parallel overlapping chasers respectively carried by the slides and having cutting-edges formed opposite their overlapping edges, means for preventing the said chasers from being deflected from parallelism when cutting, and means for moving the slides in opposite directions.

9. A collapsing tap comprising a head, a pair of oppositely movable chasers carried thereby, and having sliding abutting faces, and means on the said head providing bearing support upon opposite sides of the cutting-edges of the respective chasers against the cutting strains on the said chasers tending to deflect their longitudinal axes out of parallelism.

10. A collapsing tap comprising a head, a pair of oppositely movable chasers carried thereby, and having sliding abutting faces, a rotary cam-ring mounted upon said head and co-acting with the said chasers for controlling their movement in opposite directions, and means on the said head acting upon the said chasers upon opposite sides of their cutting-edges for supporting the said chasers against those cutting strains which tend to deflect their longitudinal axes out of parallelism.

11. A tap or reamer comprising a stock carrying a relatively longitudinally movable head, oppositely movable slides carried by said head, axially projecting overlapping cutters carried by said slides, and releasable means for adjusting said slides controlled by relative longitudinal and rotary movement between said stock and said head.

12. A tap or reamer comprising a stock,

a head longitudinally movable thereon, a pair of overlapping slides interlocked With said head'and movable transversely thereof, and a rotatable cam ring mounted on said head and releasably engaging said stock, said cam ring having opposite cam surfaces for simultaneously moving said slides in opposite directions. 7 1

18. A tap or reamer comprising a stock, a head movable longitudinally of the stock and carrying oppositely movable lapping cutter members, and a cam rotatable relatively to the head upon longitudinal movement oi the head for controlling said butters. r

r JAMES FRASER 

